Triethylamine → 7-{4-[4-(6-Ethyl-pyridin-2-yl)-piperazin-1-yl]-butoxy}-3,4-dihydro-1H-[1,8]naphthyridin-2-one

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Reaction Steps

To a solution of 1-(6-ethyl-pyridin-2-yl)-piperazine (0.41 g, 2.13 mmol) in dichloroethane (15 mL) was added Et3N (0.22 g, 2.13 mmol) and the mixture was stirred for 5 min. 4-(7-Oxo-5,6,7,8-tetrahydro-[1,8]naphthyridin-2-yloxy)-butyraldehyde (0.50 g, 2.13 mmol) was added as a solution in dichloroethane (3 mL) and the mixture was stirred at room temperature for 15 min. NaBH(OAc)3 (0.63 g, 3.00 mmol) was added as a solid and the reaction was stirred at room temperature for 2 h. The reaction was quenched with saturated NaHCO3 and extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4 and concentrated. Purification by liquid chromatography (Biotage 40M, gradient elution 100% CH2Cl2 to 99% CH2Cl2/MeOH) afforded the title compound as a sticky white foam (413 mg, 1.01 mmol, 47%). The foam was dissolved in Et2O and treated with anhydrous HCl gas to give a white precipitate. The mixture was filtered and dried to give a white powder (287 mg). MS: APCI: M+1: 410.3 (Exact Mass: 409.25).

Provenance & Evidence